add_action('rest_api_init', function () {
  register_rest_route('gg/v1', '/related/', [
    'methods'  => 'GET',
    'callback' => 'gg_get_related_arrests',
    'args'     => [
      'post_id'     => ['required' => true],
      'category_id' => ['required' => true],
      'arrest_date' => ['required' => true],
      'page'        => ['default' => 1],
    ],
    'permission_callback' => '__return_true',
  ]);
});

function gg_get_related_arrests($data) {
  $args = [
    'post_type'      => 'post',
    'posts_per_page' => 4,
    'paged'          => $data['page'],
    'post__not_in'   => [$data['post_id']],
    'cat'            => $data['category_id'],
    'meta_query'     => [
      [
        'key'   => 'arrest_date',
        'value' => $data['arrest_date'],
        'compare' => '='
      ]
    ]
  ];

  $query = new WP_Query($args);
  $results = [];

  foreach ($query->posts as $post) {
    setup_postdata($post);
    $thumbnail = get_the_post_thumbnail_url($post->ID, 'medium');
    $results[] = [
      'title' => get_the_title($post),
      'link'  => get_permalink($post),
      'image' => $thumbnail
    ];
  }
  wp_reset_postdata();
  return $results;
}